Multilin 845

The Multilin™ 845 Transformer Protection System is a member of the Multilin 8 Series protective relay platform and has been designed for the protection, control and management of 2- and 3-winding power and distribution transformers in both utility and industrial applications.

The Multilin 845 provides advanced functionality for a wide range of transformer applications delivering high-speed protection, customizable programmable logic, advanced transformer monitoring and diagnostics, and support for the latest communications protocols for easy integration into new or existing power systems.

The Multilin 845 delivers comprehensive transformer health monitoring, diagnostics, and reporting with integrated connectivity to composite and multiple gas transformer DGA solutions such as, GE’s Kelman Transformer Monitoring devices, delivering actionable analytics for asset optimization and transformer life extension.

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Key Benefits

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• Comprehensive transformer protection including fast operating differential protection, unique CT saturation and directional detection

• Advanced transformer monitoring, diagnostics and disturbance recording extending asset life

• Integrated protection & DGA for continuous transformer monitoring

• Integrated arc flash detection using light sensors to reduce incident energy and equipment damage

• High-end cyber security tools such as AAA, Radius, RBAC, and Syslog enabling NERC CIP requirements

• Draw-out design simplifies testing, commissioning and maintenance

• Optional Wi-Fi minimizes system configuration and facilitates safe relay programming and diagnostic retrieval

• Monitored environmental conditions helps reduce system downtime

• High flexibility for customized protection and control logic

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Multilin 845 Overview

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The 845 has been designed for the protection, control and management of 2- and 3-winding power and distribution transformers in both utility and industrial applications. The 845 delivers comprehensive transformer health monitoring, diagnostics, and reporting with integrated connectivity to single and multi-gas transformer DGA solutions such as, GE’s Kelman Transformer Monitoring devices, delivering actionable analytics for asset optimization and life extension.

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Applications

• Primary and back-up protection and management of small, medium and larger power and distribution transformers, autotransformers and reactors

• Designed for Utility (Transmission & Distribution) or Industrial applications

• Integrated transformer protection, monitoring diagnostics and transformer health visualization

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Percent Differential Protection

The 845 provides enhanced security by including both restrained and unrestrained (instantaneous) differential protection. The percent differential element is based on a configurable dual-breakpoint/dual-slope differential restraint characteristic with inrush and over excitation inhibits based on 2nd & 5th harmonics. The restraint current is calculated as a maximum of the internally compensated currents for better through-fault stability under CT saturation conditions.

The percent characteristic allows the element to account for both DC and AC saturation of the current transformers.

The “cubic spline” curve characteristics enable the relay to perform accurately for restraint current in range between the two slope breakpoints

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Integrated Arc Flash Protection

The Multilin 8 Series supports an integrated arc flash module providing constant monitoring of an arc flash condition within the switchgear, motor control control centers, or panel boards. With a 2ms protection pass, the 8 Series is able to detect light and overcurrent using 4 arc sensors connected to the 8 Series relay. In situations where an arc flash/fault does occur, the relay is able to quickly identify the fault and issue a trip command to the associated breaker thereby reducing the total incident energy and minimizing resulting equipment damage.

Self-monitoring and diagnostics of the sensors ensures the health of the sensors as well as the full length fiber cables. LEDs on the front panel display of the 845 can be configured to indicate the health of the sensors and its connections to the relay.

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Monitoring & Diagnostics

The Multilin 845 includes high accuracy metering and recording for all AC signals. Voltage, current, and power metering are built into the relay as a standard feature. Current and voltage parameters are available as total RMS magnitude, and as fundamental frequency magnitude and angle.

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Data Logging & Learned Data

The 845 captures key electrical and DGA data values during transformer energization to trend and analyze transformer performance. Data is summarized and presented to operators through a pre-formatted Health Report to clear indication of changes to measured parameters. Up to 365 records are supported within the 845 relay. Up to 365 latest records are supported in the 845 relay. The data, when input cumulatively to the transformer model screens helps in visualizing trends and correlating key transformer electrical and DGA parameters.

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Trip and Close Circuit Monitoring

The 845 relay provides Trip and Close Circui Monitoring elements

Breaker Arcing Current

This element calculates an estimate of the per-phase wear on the breaker contacts by measuring and integrating the current squared passing through the breaker contacts as an arc. When the threshold is exceeded in any phase, the relay can set an output operand and set an alarm.

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Breaker Health

The 845 relay provides breaker health information by monitoring and analyzing the operation count, arcing energy of breaking current, arcing time, tripping time, closing time and spring charging time if applicable.

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Integrated Electrical and DGA for Comprehensive Transformer Monitoring & Diagnostics

The Multilin 845 offers advanced transformer health monitoring and diagnostics through advanced notification of potential issues before they become critical. The Multilin 845 features detailed learned data, summarized pre/post-fault records, and integration with GE’s DGA devices to collect, trend, and analyze a transformer’s fault gasses. This enables operators to minimize costly unplanned outages and equipment failures.

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Environmental Monitoring

The 845 implements a patented environmental monitoring system that measures and provides operating condition information. Reliable and secure operation of the 845 relay and other electronic devices in the vicinity may be affected by environmental factors. The 845 relay has been designed to meet or exceed all required industry standards. Some operating conditions may be beyond those standards and reduce total lifespan of the device.

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Communications

The 845 provides advanced communications technologies for remote data and engineering access, making it easy and flexible to use and integrate into new and existing infrastructures. Direct support for copper/fiber optic Ethernet provides high-bandwidth communications, allowing for low-latency controls and high-speed file transfers of relay fault and event record information. The 845 also supports two independent IP addresses, providing high flexibility for the most challenging of communication networks. Two independent network ports enables the 845 to connect with the primary protection network and the secondary monitoring network to deliver integrated asset monitoring and diagnostics by combining protection and DGA data.

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Providing several Ethernet and serial port options and supporting a wide range of industry standard protocols, the 845 enables easy, direct integration into DCS and SCADA systems.

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